Relation Between MA and VR

Q.

Derive a relationship between mechanical advantage, velocity ratio and efficiency of a machine.

Q. With reference to the terms mechanical advantage, velocity ratio, and efficiency of a machine, name and define the term that will not change for a machine of a given design

Q.

Define $1$ erg of work and establish a relationship between erg and joule.

Q.

The correct relationship betwen the mechanical advantage (M.A.), the velocity ratio (V. R.) and the efficiency $\eta$ is :

(a) $M.A=\eta \times V.R.$ (b) $V.R=\eta \times M.A$

(c)$\eta =M.A\times V.R$ (d) none of these.

Q.

Does work done by the gravity depends on the path covered by object?

Q. The relationship between the mechanical advantage (MA), the velocity ratio (VR) and the efficiency (n) is:

1. M.A = $n\times V.R$

2. V.R. = $n\times M.A$

3. M.A = $n^2\times V.R$

4. n= $M.A\times V.R$

Q.

(a) State the relationship between mechanical advantage, velocity ratio and efficiency.

(b) Name the term that will not change for a machine of a given design.

Q.

Select the incorrect statement :

(a) A machine always has the efficiency less than $100\%$.

(b) The mechanical advantage of a machine can be less than 1.

(c) A machine can be used as a speed multiplier.

(d) A machine can have the mechanical advantage greater than the velocity ratio.

Q.

What is the condition for mechanical advantage to be less than 1 and velocity ratio to be greater than 1?

Q.

How is the mechanical advantage related to the velocity ratio fro (i) an ideal machine, (ii) a pratical machine ?

Q.

How is the mechanical advantage related with the velocity ratio for an actual machine ? State whether the efficiency of such a machine is equal to 1, less than 1 or more than 1.

Q.

In a tug of war, one team is slowly giving way to the other. What work is being done, and by whom?

Q. Can a machine have mechanical advantage greater than its velocity ratio? Explain briefly with the reason for your answer. $\left[2\text{marks}\right]$

Q.

Check if in this case, work is done and why?

A man standing at a place and holding a suitcase in hand.

Q.

What is the magnitude of mechanical advantage and velocity ratio of an actual machine?

Q.

Why Do We Prefer AC Over DC For long-distance transmission

Q.

Define Velocity ratio with reference to a machine?

Q.

A force acts on a body and displaces it by a distance $S$ in a direction at an angle $\theta$ with the direction of force. What should be the value of $\theta$ to get the maximum positive work?

Q.

A machine has a velocity ratio of 4. If it is used to raise a load of 400 N by 4 m using an effort of 200 N, find the work done on the machine. Take g = 10 m/s${}^2$.

1. 3200 J

2. 6400 J

3. 2000 J

4. 1600 J

Q.

Complete the following sentences :

(a) Mechanical advantage = ............ $\times$ velocity ratio

(b) In class II leer, effort arm is ........ than the load arm.

(c) A scissors is a ........ multiplier

Q.

A work of $1000J$ is done on a body in $4s$, such that a displacement of $20m$ is caused. Calculate force.

Q.

Name the property of an object due to which it tends to maintain its state of rest or of uniform motion along a straight line.

Q. How much energy is gained by a box of mass $20kg$ when a man raises the box by $0.5m$ in order to place it inside the bus? $(g=10m{s}^{-2})$

Q.

Can a body at rest be in motion?

Q.

In angle in between the direction of applied force and displacement, for maximum work should be

1. 90°

2. 45°

3. zero

4. 30°

Q.

In a bottle opener, the fulcrum is:

1. At the end

2. In the middle

3. At the load point

4. At the effort point

Q.

No work is done when an object moves

1. along the direction of force

2. opposite to the direction of force

3. at any angle to the direction of force

4. at 90° to the direction of force

Q. ntA car is moving on a frictionless surface. If engine delivers constant power, then how does displacement x of car varies with time t?n

Q.

The relationship between MA and VR for i) an Ideal machine and ii) a Real machine

1. 

2. 

3. 

4. 

5. 

Q.

How is the mechanical advantage related to the velocity ratio for (i) an ideal machine, (ii) a practical machine?